BIOPRINTING

June 19, 2016

If you have read my posts over the past few months you will be very familiar with 3-D printing. “Additive” manufacturing is a disruptive technology that is changing the manner in which components are made. Once again, let us look at the definition of 3 D printing relative to “rapid prototyping”.

A 3D printer is a computer-aided manufacturing (CAM) device that creates three-dimensional objects. Like a traditional printer, a 3D printer receives digital data from a computer as input. However, instead of printing theoutput on paper, a 3D printer builds a three-dimensional model out of a custom material. (For our purposes, the words “custom materials” are the key words.)

3D printers use a process called additive manufacturing to form (or “print”) physical objects layer by layer until the model is complete. This is different than subtractive manufacturing, in which a machine reshapes or removes material from an existing mold. Since 3D printers create models from scratch, they are more efficient and produce less waste than subtractive manufacturing devices.

There are several viable options available today that take advantage of rapid prototyping technologies. All of the methods shown below are considered to be rapid prototyping and manufacturing technologies.

(SLA) Stereolithography

(SLS) Selective Laser Sintering

(FDM) Fused Deposition Modeling

(3DP) Three Dimensional Printing

(Pjet) Poly-Jet

Laminated Object Manufacturing

The process of “additive” manufacturing is finding more and more uses as the availability of desirable materials improves. At one time, during early phases of 3-D development, materials suitable for printing were very limited with only a few finding acceptance. Even then, most 3-D printing was used to product prototypes and not “workable” goods used for long-term use. That has all changed. Additive manufacturing is now being considered for production as well as prototyping.

The June 2016 edition of “Manufacturing Engineering” had a fascinating article entitled “Bioprinting Helping Researchers Understand How Cells Work”. Bioprinting is a new word to me with a definition as follows:

“ Bioprinting is the three-dimensional printing of biological tissue and organs through layering of living cells. While this area of manufacturing is still in the experimental stage and is currently used primarily in scientific study rather than applied science, the possibility of creating functional replacement tissues or organs could one day transform medical treatment.”

Every day new applications for 3D printing are being discovered. Whether it’s 3D printing drones with the electronics built into them, or 3D printing human tissue for drug toxicity testing, the research being done and discoveries being made are often times unbelievable. The area of 3D bioprinting is probably one of the most interesting applications of additive manufacturing. It’s quite clear that someday in the not too distant future many of us will eventually have 3D printed body parts both inside and outside our bodies. The prospects of bioprinting are staggering. As the technology develops over the coming decades, individuals will begin receiving bioprinted organs and other biological components, there is no doubt that the term ‘bioprinting’ will become a commonly used word within the English vocabulary.

Bioprinting begins with creating an architectural design based on the fundamental composition of the target tissue or organ. Pre-bioprinting is the process of creating a model that the printer will use to later create and choose the materials that will be used. One of the first steps is to obtain a biopsy of the organ. The common technologies used for bioprinting are computed tomography (CT) and magnetic resonance imaging (MRI). In order to print with a layer-by-layer approach, tomographic reconstruction is done on the images. The now-2D images are then sent to the printer to be made. Once the image is created, certain cells are isolated and multiplied. These cells are then mixed with a special liquefied material that provides oxygen and other nutrients to keep them alive. In some processes, the cells are encapsulated in cellular spheroids 500μm in diameter. This aggregation of cells does not require a scaffold, and are required for placing in the tubular-like tissue fusion for processes such as extrusion. In a laboratory environment, a bioprinter then uses that design and deposits thin layers of cells using a bioprint head, which moves either left and right or up and down in the required configuration. Bioprinters use bio-ink, or bioprocess protocols, to build these organic materials. They also dispense a dissolvable hydrogel to support and protect cells as tissues are constructed vertically, to act as fillers to fill empty spaces within the tissues.

As you can imagine, the equipment used to bioprint human parts is remarkably specialized and used within a clean room environment to eliminate infection of the part or organ when surgically applied to a patient. The three digital photographs below will illustrate two applications of equipment.

As mentioned earlier, bioprinting , for the time being, is experimental in nature but very very promising. Considerable work is being accomplished to bring this form of additive manufacturing to the medical field. The nose and ear shown below indicate two body parts that will be surgically applied to an individual.

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